JP3173041B2 - Wafer polishing apparatus with dresser and method for dressing polishing cloth surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer polishing apparatus for mirror-polishing a wafer made of silicon semiconductor or the like and a method of dressing a polishing cloth surface thereof.

[0002]

2. Description of the Related Art A conventional wafer polishing apparatus mounts a wafer on a lower surface side of an axially rotating top ring, and presses the wafer against a polishing cloth stuck on an upper surface of a turntable to perform mirror polishing. JP-A-64-2
No. 857).

[0003]

In this type of wafer polishing apparatus, the surface of the wafer is polished to a mirror surface by the frictional force caused by the relative sliding between the wafer and the slurry supplied to the polishing cloth surface. If the surface of the polishing cloth becomes rough, such as fluffing or waving, the polishing accuracy is adversely affected. Further, the outer peripheral portion of the portion of the polishing cloth passing through the wafer is inclined, so that the wafer cannot be polished flat. In such a case, it was not possible to correct the roughness or inclination of the polishing pad by stopping the machine during polishing, but only to correct before polishing the next wafer after polishing. However, it is very troublesome to correct the roughness or inclination of the surface of the polishing cloth each time before the wafer polishing operation, and the polishing operation efficiency is lowered.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional problems, and has a dresser-equipped wafer polishing apparatus and a polishing apparatus capable of simultaneously correcting the roughness and inclination of the surface of a polishing cloth during a wafer polishing operation. An object of the present invention is to provide a method of dressing a cloth surface.

[0005]

As a means for technically solving this problem, according to the present invention, a wafer is mounted on the lower surface side of a rotating top ring, and the wafer is mounted on the upper surface of a turntable. In a wafer polishing apparatus for mirror-polishing by pressing against a polishing cloth, a top ring holding portion is fixed to a lower end of a rotating main shaft formed to be vertically movable, and the rotating main shaft is cup-shaped so as to cover the top ring holding portion. The gist of the present invention is a dresser-equipped wafer polishing apparatus in which a dresser is mounted so as to be freely rotatable via a bearing, and a correction ring is attached to a lower peripheral edge of the dresser to form a top ring. In this wafer polishing apparatus with a dresser, a weight for adjusting a pressing force against the polishing pad is placed on the dresser. Further, the present invention uses a wafer polishing apparatus with a dresser on which the weight is placed, suction-fixes the wafer to the wafer chuck, applies a constant fluid pressure to the closed space, and presses the wafer against the polishing cloth. While rotating the turntable and the top ring to polish the wafer, the dresser is free to rotate with respect to the rotation of the top ring main body, and the correction ring is brought into contact with the polishing cloth to correct the roughness of the polishing cloth surface, and the dresser The gist of the present invention is a dressing method for a polishing cloth surface in which the pressing force of a correction ring against the polishing cloth is adjusted by increasing or decreasing the weight placed on the upper part.

[0006]

During the polishing of the wafer, the dresser having the correction ring provided on the outer periphery of the top ring follows the same path as the top ring with respect to the polishing cloth on the turntable. Roughness and inclination of the surface of a typical polishing cloth can be corrected. At this time, by increasing or decreasing the weight placed on the upper part of the dresser, the pressing force of the correction ring against the polishing cloth can be adjusted, and the dressing of the polishing cloth surface can be properly performed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In FIG. 1, reference numeral 1 denotes a rotating spindle which is formed so as to be able to move up and down, and an inverted dish-shaped top ring holding section 2 is fixed to a flange section 1a at a lower end thereof so that the axis coincides with the rotating spindle 1.

A top ring body 3 has a plurality of wafer chucks 4 fitted and fixed to the lower surface thereof, and each wafer chuck has a large number of through holes 4a vertically penetrating therethrough. The ring body 3 has an opening in a concave portion 3b provided in the base plate 3a.

Reference numeral 5 denotes a substantially ring-shaped elastic body made of rubber or the like, and the top ring main body 3 is suspended by the top ring holding section 2 via this elastic body. That is,
The inner peripheral edge of the elastic body 5 is attached to the outer peripheral part of the lower surface of the top ring body 3 by a ring-shaped pressing member 6 and a stopper 8, and similarly, the outer peripheral edge of the elastic body 5 and the ring-shaped pressing member 7
And a stopper 9 attached to the outer peripheral portion of the lower surface of the top ring holding portion 2. Therefore, the top ring body 3 is
It is possible to freely move via the elastic body 5 independently of the top ring holding portion 2. The elastic body 5 has a closed space 10 between the top ring holding portion 2 and the top ring main body 3.
Can be formed.

Reference numeral 11 denotes a fluid supply nozzle, which is provided at the center of the rotary main shaft 1 along the axial direction, and has a lower end opening in the closed space 10 and is compressed by a fluid supply device (not shown). Air can be supplied.

Numeral 12 denotes a fluid discharge nozzle, a plurality of which are arranged side by side in parallel so as to surround the fluid supply nozzle 11 in the rotary spindle 1, and a connecting pipe 13 is connected to a lower end thereof. The distal end of the tube 13 is connected to an introduction tube 14 attached to the base plate 3a of the top ring main body 3, and the introduction tube 14 opens to the recess 3b. Therefore, the fluid discharge nozzle 12 communicates with the through hole 4a of the wafer chuck 4 through the connection pipe 13, the introduction pipe 14, and the recess 3b.

Reference numeral 15 denotes a dresser assembled in a substantially cup-like shape. The dresser 15 completely covers the top ring holding portion 2, and a central boss portion 15 a is rotatably fitted to the rotary spindle 1 via a bearing 16. A correction ring 17 is attached to the peripheral edge of the lower end.

Reference numeral 18 denotes a ring-shaped weight placed on the dresser 15.

The top ring R with a dresser thus configured is used by being incorporated in a known wafer polishing apparatus as shown in FIG. 3, and in this case, the wafer W is sucked and fixed by the wafer chuck 4, A compressed air is blown into the closed space 10 to polish the polishing cloth C on the turntable T.
Polishing is performed by pressing the wafer W against the wafer. Although not shown, a polishing slurry is supplied to the center of the turntable T.

At this time, the turntable T and the top ring R are rotated while adjusting the fluid pressure so that the pressure inside the closed space 10 is kept constant. The turntable T is rotated by forcible driving, and the top ring R may be either forcible driving or free rotation (co-rotation by rotation of the turntable).

In such a polishing process, the dresser 15 is free to rotate independently of the rotation of the top ring R with the rotation of the turntable T, and the correction ring 17 comes into contact with the polishing cloth C so that the dressing Surface roughness can be corrected.

That is, during the polishing of the wafer W, the surface of the polishing pad C can be corrected at the same time.
Is located on the outer periphery of the top ring R, so that the surface of the polishing cloth C is evenly distributed in the circle slightly larger than the polishing area of the wafer W along the circumferential direction of the turntable T. I can do it.

Therefore, the surface of the polishing cloth C is corrected when entering the correction ring 17, and after the correction, the polishing cloth C comes into contact with the wafer W, so that the polishing accuracy can be remarkably improved. Since the surface is also corrected when leaving, the roughness of the surface after polishing is immediately corrected. That is, the polishing cloth C is double-corrected by the correction ring 17 both before and after the polishing of the wafer W.

The pressing force of the correction ring 17 against the polishing cloth C can be easily adjusted by increasing or decreasing the weight 18. The dresser 15 is attached to the rotating main shaft 1 via a bearing 16, and is not directly fixed to the rotating main shaft 1 by welding or the like. Therefore, the weight 18 can be placed on the dresser 15 and pressed by the play (slight play) of the bearing 16.

[0020]

As described above, according to the present invention,
Since a dresser having a correction ring is provided on the outer periphery of the top ring of the wafer polishing apparatus, it is possible to simultaneously correct local roughness and inclination of the polishing cloth while polishing the wafer, thereby improving the accuracy of the wafer polishing process. At the same time, the conventional troublesome work of repairing the polishing cloth, which has been performed separately from the polishing, becomes unnecessary, and the efficiency of the polishing operation can be improved. Furthermore, since a cup-shaped dresser having a correction ring is attached to the rotating spindle for rotating the top ring so as to be freely rotatable via a bearing around the rotating spindle, the top ring and the dresser do not collide with each other.
In addition, since the dresser can be easily moved by raising the rotating spindle, there are excellent effects such as extremely easy handling of the dresser.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing an embodiment of the present invention.

FIG. 2 is a bottom view of the main part.

FIG. 3 is an explanatory diagram showing a use state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotating main spindle 1a ... Flange part 2 ... Top ring holding part 3 ... Top ring main body 3a ... Base plate 3b ... Concave part 4 ... Wafer chuck 4a ... Through hole 5 ... Elastic body 6, 7 ... Holding member
8, 9 ... Stopper 10 ... Sealed space 11 ... Nozzle for fluid supply
12 ... Nozzle for fluid discharge 13 ... Connection pipe 14 ... Introduction pipe 15 ... Dresser 15a ... Boss 16 ... Bearing 17 ... Modification ring 18 ... Weight R ... Top ring W ... Wafer T ... Turn table C ...
Polishing cloth

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Claims (3)

(57) [Claims] 1. A wafer polishing apparatus which mounts a wafer on a lower surface side of an axially rotating top ring and presses the wafer against a polishing cloth mounted on an upper surface of a turntable to mirror-polish the wafer. A top ring holding portion is fixed to the lower end of the main shaft, and a cup-shaped dresser is attached to the rotating main shaft so as to cover the top ring holding portion via a bearing so as to be freely rotatable. A wafer polishing apparatus with a dresser, wherein a top ring is formed by attaching a correction ring. 2. The wafer polishing apparatus with a dresser according to claim 1, wherein a weight for adjusting a pressing force against said polishing pad is placed on said dresser. 3. A wafer polishing apparatus with a dresser according to claim 2, wherein the wafer is suction-fixed to the wafer chuck, a constant fluid pressure is applied to the closed space, and the wafer is pressed against a polishing cloth. While rotating the top ring to polish the wafer, the dresser is free to rotate with respect to the rotation of the top ring main body, and the correction ring is brought into contact with the polishing cloth to correct the roughness of the polishing cloth surface, and is placed on the dresser. A dressing method for a polishing cloth surface, wherein the pressing force of the correction ring against the polishing cloth is adjusted by increasing or decreasing the placed weight.